Nowadays, refrigerators have become a common appliance in virtually every household and typically are used for storage and preservation of food in particular of fresh food such as fruits, vegetables, dairy products, and the like. It is desirable to keep the food items fresh as long as possible in the refrigerator.
It is a well known problem that many food items tend to release malodors into the air which are then captured in the limited air space in a refrigerator. Not only are these malodors unpleasant and offensive to the user of the refrigerator, they can also have a negative impact on the quality of other foods in the refrigerator. For example, it is known that some foods emit strong odors (e.g. fish, boiled eggs, onions, etc.) and that these odors can transfer to other nearby foods and hurt the taste and freshness of those foods. A common example is transfer of odors into an open container of orange juice or of milk resulting in a noticeable degradation in their taste. It is also well known that malodors from some vegetables (onions, garlic) can transfer to other foods stored within a vegetable drawer. This problem is aggravated when the vegetable drawer is sealed such that there is very little air exchange with the larger compartment of the refrigerator (herein referred to as the “fresh food compartment”) and when vegetables have been cut or are stored without any outer wrapping. This problem of odor transfer is particularly acute in the case of ice cubes where odors from the fresh food compartment of the refrigerator can be transferred to the ice in the freezer compartment of the refrigerator. This is especially true in the case of refrigerators in which there is air exchange between the fresh food and freezer compartments, and especially in the case of refrigerators with built-in ice-makers.
In addition to malodors, however, fruits and vegetables are known to produce ethylene as a part of their normal ripening process. Unfortunately this ethylene also contributes to the degradation of ethylene sensitive foods, primarily vegetables like broccoli, lettuce, green peppers, etc. Ethylene-producing and ethylene-sensitive fruits and vegetables are well known.
U.S. Pat. No. 5,403,548 discloses an activated carbon absorbent to be used for example in refrigerators, shoe boxes, closets, toilets, cars, cupboard, or the like. The activated carbon absorbent is applied in a gas treating apparatus comprising an air inlet, and air outlet, a cylinder housing the activated carbon honeycomb, and a fan aspiring malodor through the air inlet. Change of battery and withdrawal of the cylinder housing the activated carbon are achieved by dismounting the cover of the apparatus. The gas treating apparatus may further comprise an action means for alerting the user to the event that the useful life of the activated carbon adsorbent has run out. This gas treating apparatus has the disadvantage that it is not capable of removing ethylene from the air.
It is therefore an object of the present invention to provide an air filtering device which overcomes the disadvantages of the prior art devices.
It is a further object of the present invention to provide an air filtering device which is capable of removing both malodors and ethylene from the air.